The next installment of our conservation webinar series takes place March 22nd and looks at exciting research into Cougar prey choice.
Siobhan Darlington, (UBC Okanagan | Southern BC Cougar Project), will present her research on spatial and seasonal variation in cougar prey choice in the southern interior of British Columbia.
In southern British Columbia, cougars are the main proximate source of mortality for declining mule deer and bighorn sheep populations. Habitat disturbance from forestry, roads, agriculture, and wildfire are cumulatively changing the landscape for predators and their prey.
The objectives of this study were to compare habitat characteristics at cougar kill sites across seasons and quantify prey > 8 kg in their diet. We deployed 48 GPS collars on adult cougars (33 females, 15 males) across three study areas along the international boundary in southern BC; these include the West Okanagan (5,800 km2) eastward to the Boundary (5,200 km2), and the Kootenays (3,800 km2).
The study used cluster analysis to investigate 1,300 cougar cluster sites, identifying 870 kills from 38 individuals. Mule deer comprised the largest proportion of cougar diet (43.5%) followed by white-tailed deer (Odocoileus virginianus; 26.1%), unidentified deer species (10.7%), elk (Cervus elaphus; 10.4%), moose (Alces alces; 6.76%), and other prey (2.5%). However, prey choice differs by study area and season, with a greater proportion of mule deer and moose in cougar diet in the West Okanagan and gradually more white-tailed deer and elk farther east.
The next phase of the project will assess patterns of cougar kill site selection in relation to landscape disturbance. These data will be used to inform provincial wildlife managers on the effects of human and natural disturbance types on cougar behaviour and predation pressure on ungulate species of concern in southern British Columbia.